GEOL. C ROAT . 50/2 1 151 . 155 1 I ZAGREB 1997 Professor Herak's Contribution to Triassic Stratigraphy Georg KOCH and Tonci GRGASOVIC Abstract The beginning of Prof. Herak's sc ientific career was linked to (he problems of the Triass ic stratigraph y. He resolved the Triassic stratig­ raphy o f some parts of the Croatia n Dinaridcs by using dasyclad algae. Sazetak Pocelak karijere pro fes ora Milana Heraka bio je vczan za pro­ blernatiku stratigrafije trijasa. Stratigrafiju trijasa pojedinih dijelova hrvatskih Dinarida ljdavao jc korislcci daziklndalnc algc. "The Triassic within the Dinarides is very well developed, thus representing a very important part of the Mediterranean Triassic" (HERAK, 1984, p. 205) Professor Herak 's scientific work can be divided into a tripartite, informal chronological division: "Early Herak" comprises the work on Triassic problems, "Mi­ ddle Herak" incl udes the research on Karst phenome­ non and " Late Herak " charac terises the effort to con­ tri ve a proper structural and geodynamic model of the Dinarides. The "Early Herak" period lasted approximately thir­ ty years and it seems to be that Herak owes his interest in the Triass ic to the geological work undertaken within the research team of Pro fesso r Salopek, and also possi­ bly to his subsequent PhD studies, guided by Julius von Pia in Vienna (HERAK, 1943, 1944). His first stratigraphic work (HERAK, 1947) dea ls with the stratigraphic division of the Mesozoic deposits of his native Zumberak Mt. area. In a series of publica­ tions (HERAK, 1954a, b, 1955) , he reported on the geo logy of the neighbouring Samobor Mountain. Sub­ sequently, he published his significant work "Geology of the Samobor Mountain" (H ERAK, [956a) in which very detailed descript ions on the stratigraphic and tec­ tonic relationships were given, especially for the Trias­ sic. His research showed clearly tha t the distribution of the Tri ass ic within the inves ti ga ted area was much more extensive than was earlier presumed, and for the gypsum deposits, previously attributed to the Early Tri­ assic, he indicated Palaeozoic age. [-Ie also ditTcrenti­ atcd the Middle Triassic (Ladinian), mixed shale-marl- Institu[e of Geology, Saehsova 2. P.O. Box 268, HR- IOOOO Zagreb, Croati a. limestone successions, with tuffs and chcrts, as well as the Late Triassic dolomites . The widespread carbonate successions of the Zumberak Mountain were also proven to be Late Triassic in age (HERAK et aI., 1965). The lates t paper on the Triassic from his native Zumbe­ rak, date [rom the end of the 1960 's (HERAK, 1966c, 1968). Nevertheless, he is nowadays still connected 10 the Zumberak stratigraphy as a referee on the main pro­ ject of the geo[ogiea[ map [:50,000 of the Repub[ic of Croatia. Within the regional fram ework of geological research, Herak investigated the area of Kordun and Lika (HERAK, [954e, 1956c). There, in the area of the Korana river, he di scovered wid espread Triassic deposits, especially dolomites, overlain by the Early Jurassic (Liassic) dolomites. Subsequently, HERAK & BAHUN ( [963) and HERAK & BOlANIC (1966) investigated the Triassic in greater detail, proving that this area is characterized by Early and Late Triassic suc­ cessions. In a series of publications (HERAK, 1952a, b, 1956a, 1957, 1962, 1963 , 1966b, 1968; HERAK & BAHUN, [963; HERAK & BOJANIC, [966), Herak uses the "algae" Sphaerocodium borJlemal1J1i as proof of the identification of Late Triassic deposits. Although it was later proven that such findings are not "algae" but sedimento[ogiea[ structures· oneoids (BABIC, J 970), the deposi ts characterized by oncoids remain during the geological mapping as an indicator of Late Triassic This paper was presented at the scientific meeting dedicated to the 80th anniversary of the life of Professor Milan Herak, held on March 5th, 1997 in Zagreb I)", deposits, where these oncoids often occur in high num­ bers. HERAK ( 1950) pointed ou t the great significance of the use of dasyc1ad algae in the division of thc Triassic successions, linking through this approach his two research fields. In the area of Gracac, HERAK (1956b) separates the Anisian from the Ladinian deposits on the basis of their dasyclad flora, and proved the discontinu­ ity bctwcen the Ladin ian and Carnian. In the same area, HERAK (1960c) identified the disconti nuity between the Permian and the Triassic, proved the Middle Trias­ sic, and complcted thc interpretation of the discontinu­ it y bctween the Middle and Late Triassic. Having investigatcd the Triassic in the vicinity of Sv. Rok in Lib, HERAK (1965) confirmed once more the great value of the dasyc1ad algae in the stage division of the Middle Triassic, and revised some of the known stra ti ­ graphic ranges or certain species. Herak synthesised his knowledge and that of other geologists and he presented it rcgularly at home as well as to the world-wide scientific community. The Triassic stra ti graphy of Croatia, based on the dasyclad algae (HERAK, 1960b), was presented for the first time to the world-wide geological community at the Interna­ tional Geological Congress in Copenhagen. At the International Colloquium on the Triassic in Montpellier in 1961, HERAK (1962,1963) showed the main bio­ stratigraphic, lithological and palaeogeographical rela­ tionships of the Triassic in Croatia, emphasising the role of certain orogenic phases on the formation of the Triassic successions and their final distribution. In the lecture, held in thc Vienncse Geological Society, HER­ AK (1966a) emphasized the role of dasyclad algae in the stratigraphy of thc Dinarides. At the Slovakian international Colloquium on the Triassic Stratigraphy, HERAK et al. (1967) presented a correlation of the Tri­ assic or Lika, Paklcnica and Gorski Kotar , with the revicw of thc fossil dasyclad assemblage. Subsequently, HERAK ( 1973b) presented the resu lts of the investiga­ tion of the Triassic in Croatia, and in HERAK (1987b) a review of thc Triassic of the Dinarides in the light of thc transition between Hercynian and Alpine orogenic phases. At the Viennese International Symposium on the Alpine-Mediterranean Triassic Stratigraphy, HERAK (1974a) gave a precis of the results of h is work on the research of the Triassic in the Dinarides, with the emphasis on the palaeogeography and facies. By doing this, he highlighted the problems which remain topical today: "The palaeogeographic conditions of the facies development during Triassic of a relatively narrow belt of the Croatian Dinarides, rel-leet the dynamics without any clear chronolog ical or facies overlapping of the bordcring layers of different stages and series. Conse­ quently, the use of chronostratigraphic units in the stratigraphi c class ification is morc difficult and more or less artificial. Therefore, lithostrat igraphic units have the advantage of application, bccause they better reflect the natural mutual relations. In these cases, the chrono- IJCOlogw LrOaliCa )U/L. strat igraphic uni ts arc treated generally and morc or less dynamically . Every attempt of squeezing that kind of dynamics into a virtual static frame, would represent suppressing of the natural relationships". At the Viennese Symposium on the Biostratigraphy of the Tethyan Triassic, HERAK et al. (1983) presented the proposal for the Stratotype of the European Upper Scythian in the area of Mue. This is one of the undoubt­ edly mosl significant contributions to the Triassic stratigraphy, which is evidenced in the generally high intcrcst among the Triassic researchers. Herak is also connected through his educational work as an university professor of stratigraphical and regional geology to his research field of Triassic strati­ graphy. On this issue, he wrote a lot in his university textbooks (HERAK, 1960a, 1973a, 1984, 1987a, 1990; TAJDER & HERAK , 1951, 1959, 1966). He contri­ buted also in resolving some of the general stratigraphic problems (HERAK, 1974b, 1975, 1976), whieh made him one of the most important advisors in the realisa­ tion of the new geological map of Croatia. Lei us conclude that Professor Herak 's contribution to Triassic stratigraphy is exceptional, by emphasising his approach of the application of the dasyclad algae to the stratigraphy, and the synthcsis of the knowledge on facies and palaeogeographic development of the Trias­ sic in Croatia. REFERENCES BABIC, Lj. (1970): Sphaerocodiu/JI or oncoids from the Upper Triassic dolomi te of wcstcrn Yugoslavia? (Sphaerocodium iii onkoidi iz gornjotrijaskog dolomita zapadnog dijela Jugoslavije?).- Geoloski vjesn ik, 23 (1969), 11 -19. HERAK, M. (1943): Zur Kenntnis triadischer Kalk­ schwamme (Sycones).- N. Jb. Min. Geol. Pal aeon!., Abh., B, 88,107-135. HERAK, M. (1944): Triaskc vapnenc spuzvc iz skup ine "Sycones" (Triadischer Kalkschwamm e aus del' Gruppe "Sycones") .- Vjesnik Hrvatskog drzavnog geolozkog zavoda, 2-3, 41-70, Zagreb. HERAK, M. (1947): Prilog stratigrafskom rasclanjiva­ nju mezozoj skih naslaga jugozapadnog dijcla Zum­ berackc gore.- Geoloski vjesnik, 1,3-5. HERAK , M. (1950): Ladinicke Dasycladaceae .lugo­ slavije i njihovo stratigrafsko znacenje.- Racl Jugo­ slavenskc akadcmije znanosti i umjetnosti, 280, 115-14l , Zagreb. HERAK, M. (1952a): Znacenje alge Sphaerocodium Bornemanlli Rothplctz za interpretaciju gornjeg tri­ jasa u podrucju Zagorske Mreznice.- Rad Ju go­ slavenske akademije znanosti i umjetnosti, 289/4, 187 -195, Zagreb. HERAK, M. (l952b): Die Bedeutung del' Alge Spliae­ roeodilllJl Bornemann! Rothpletz flir die Interprcta- Koch & Grgasovic: Professor Ilerak·s Contribution to Tri;lssic SIr:ui graphy lion del' Oberlri as im Gebiet von Zagorska Mrezni­ C;.l. - Bul letin se icntifiqu c, Consci l des Academics des Sc iences ct dcs A rts de la R.S .F. de Yougo­ slav ic, Section A: Sciences naturelles, techniques et medicales, 7, 85-88, Zagreb. HERAK, M. (1954a): IzvjcStaj 0 geoloskom istraz iva­ nju Samoborske gore II godi ni 1951.- Ljctopis JAZU , 59 (1951 - 1952), 81-83, Zagreb. l-lioRAK, M. ( 1954b): Izvj cStaj 0 geo loskim istrai iva­ njima u Samoborskoj okolin i u god ini 1952.- Ljc­ topis JAZU, 59 (195 1-1952), 84-86, Zagreb. ll ERA K, M. (1954e): 0 geoloskim prilikama pod rucja Korane uzvodno od Slunja CObcr die geologischen Verhiilt llissc des Korana Gebicles von Slunj in Kro­ ati en). - Geolosk i vjesn ik, 5-7 (195 1- 1953), 7 -24. Il ERA K, M. ( 1955): Geoloska istrazivanja u podrucju Samoborske gore.- LjelOpis JAZU, 60 (1953), 279- 280, Zagreb. IIERAK, M. (1956a): Geologija Samoborskog gorja (Geo log ie des Samoborer Gcbirge).- Acta geo lo­ gica, 1,49-73 , Zagrcb. I IERAK, M. (1956b): St ratig rarska intcrpretaeija tri ­ jaskih sed imcnata s dasikladaeejam<1 u okolici Gracaca u Hrvatskoj (S trat igraphische Interpretation triadischer Sed imentc mit Dasycladaccen cler Um­ gebung von Gracac in Kroatien).- Acta geologica, I , 149- 154, Zagreb. HERAK, M. (19560): 0 mezozo iku pudrucja Koranc iZllledu Barilovica i Poloja (Uber das Mesozoikum des Korana Gcbiclcs zwischen Ba ri lov ic li nd Pol­ oj).- Gcolosk i vjcsnik, 8-9 ( 1954- 1955),53-66. lIERAK, M. (1957): Nov i nalazi s ferokod ij a u I-Irvat­ skoj i Slovcniji (Neue Funclc von Sph{f('rocoC/iulI/ in Kroaticn lind Siowenicn) .- Gcolosk i vjesn ik, 10 ( 1956), 3 I -38. HERAK, M. (1960a): Geologija. Struktura, dinamika i ili storija Zelllljc.- Skolska knj iga, Zagreb, X I+433 p. HERAK , M. (1960b): Calcareous a lgae of the Young Palacozoic and Mesozo ic of Yugosl avia and thei r application in the stratigraphy.- In: HESSLAND, I. & EROTMAN, G. (cds .): Report o f the Twe nt y­ Firs t Session, Norden, I nternational Geolog ical Congress. Part VI , Proceed ings of Section 6, Pre­ Quaterna ry Micropaleontology. Det Berlingskc Bogtrykkeri, 90-97 , Copenhagen. HERAK, M. ( 1960e): Geologija Gracackog polja u Liei (Geologie des Karst Poljc von Gracac in def Lika, Kroatien).- Gcoloski vjesnik, 13 (1959), 3 1-56. IIERAK , M. (1962): Trias de la Yugoslavie.- Geoloski vjesnik, 15/1,301 -3 10. fIERAK , M. ( 1963): Trias de Yugoslavie. - In : Le Tri as de la France et des region s limitrophes. Mem. I3meau Reeh. Geol. Min., 15,477-454, Paris. 153 HERAK, M. (1965): Nas lagc trijasa u okolici Sv . Roka II Lici (Triasablagcrungen in def Umgebung von Sv . Rok in der Lika).- Ac ta geologica, 5, 85 - 100, Zag­ reb. H ERAK, M. (l966a) : Die Kalkalgen in de l' Strati gra­ phic cle f Dinariden (Jungpab\ozo ikum lInci Mcso­ zoik ul11). - Mi tteilungen der geologischen Gescll­ sehaft in Wien, 58 , 209-217, Wien. HERAK, M. (1966b) : Geolosko istraz ivanj e Zumbe r­ ka.- Ljetopis JAZU, 7 1 (1964),263-265, Zagreb. HERAK, M. ( 1968): Noviji rczultat i istrai.ivanja osnov­ nih stratigrafskih jcd inica u Zumbcrku (Neu Ergeb­ nisse der Untersuchungen von st ratigraphi sc hen Haupteinhcitcn in Zumberak (W Kroat ien)). - Gco­ loski vjcsn ik, 21 ( 1967), 11 1-1 16. H ERAK , M. (1973a): Geologija. St ruk tura, din::lmika i razvoj Zemlje.- 2nd cd., Skoiska knjiga, Zagreb, XII+465 p. HER AK, M. (l973b): Novija is trazivanj a trij asa u I-l rvatskoj (Neuerc Untersuchungen der T rias Kroat­ iens).- Geologija, 16,375-378, Ljubljana. H ERAK, M . ( 1974a): Pal iiogeographie li nd Fazi es­ En twick lung withrc nd der T rias in den Di nar idcn Kr03tiens.- I n: ZAPFE, H. (eeL): Die Stratigraph ic clef alpi n-medi lerrancn Tri as. Symposium (Wicn, Mai 1973) . Osterre ichische Akademie der W is­ sc nsc haften, Schriftenreihe der Erdwissellscha n­ lichen KOlllmi ssionen, 2, 101 - 106, W icn. HERAK , M. (I974b): Prineipi stratigrafske klas irika­ cije i tcrm inologije (Principles or strat igraphic clas­ sification and terminology).- Narta, 25/5. 233-236, Zagreb. HERAK, M . (1975): Some com men ts on strati graphic classification ancl terminology (Ncke primjedbc LI Z stratigrafsku intcrpretacij u i tcnninologiju).- Gco­ loski vjcsnik, 28, 55-63. HERAK, M. ( 1976): Cilj, namjcna i sadrzaj gcoloske karte SFRJ 1:50.000.- Geoloski vjcs nik, 29, 363- 374. HERAK, M. (1 984) : Geol ogija. Postanak, tektoni ka i cli namika zem ljc. Razvoj ni put zcm lje i zivotH. Gco­ loska grada kont incnata i oceana. - 3rd ed. , Skolska knj iga, Zagreb, XX+429 p. HERAK, M. (I 987a): Geolog ija. Postanak, tektoni ka i dillal1l ika zcmlje. Razvoj ni put zcm lje i zivola. Gco­ loska grada kontinenata i occana.- 4 th ee\. , Sko lska knj iga, Z agreb, XV+433 p. HERAK, M. (1987 b): T rijas Oinarida na pre law izme­ du herci nske i alpinskc orogenczc (The T ri assic of the Dinaridcs, the linking peri od of Hercynian and A lpinc orogenesis).- Zbornik radova posveccn aka­ dcmiku Z . Bcs icu, C rnogorska akademija nauka i umjelnost i, 33-38, T itograd . I .'" HERAK, M . (1 990): Geologija. Poslanak, lcktonika i dinamika zeI11lje. Razvojni put zemlje i zivota. Geo­ loska gfada kontinenata i oceana. - 5th cd. , Skolska knjiga, Zagreb, XV+433 p. HERAK, M. & BAH UN , S. ( 1963): Pril og slraligra­ fskoj anali zi nas laga u podrucju Slunj-Komesarae­ Rakoviea, J-Irvatska (Ein Beitrag zur strati graphis ­ chen Anal yse der Ablagerun gcn im Gebie t Slunj­ Komesarac-Rakovica, Kroatien).- Geoloski vjesnik, 16 ( 1962), 33-34. HERAK, M. & BOJANIC, L. (1966): Rcvi zija lrijasa u poclrucju rijekc Koranc izmeclu Barilovi ca i Slunja (Rcv ision dcr Tri asabJagerungen im Gebie t des Flusses Karana zwi sche n Barilovic und Slu nj).­ Gcoloski vjesnik, 19( 1965), 47-51. HERAK , M. , MAJCEN, Z. & KOROLlJA, 13. (1965): Pr il og paleontol o.skoj dokumenlac iji Illezozoika u Samoborskolll gOlju i SI Zumberku (Beitrag zur palaonlologischen Dokulllentation des Mezozoi­ kUI11s illl Samoborer Gebirge und dem NE Zumbe­ rak). - Geoloski vjesnik, 18/2 ( 1964), 325-332. HERAK , M. SOKAC, B. & SCA VNICAR, B. ( 1967) : Correlation of the Triass ic in SW Lika, Paklen ica and Gorski Kolar (Croalia).- Geologicky Sbornfk - Geo logica Carpathica, XVIlI/2, 189-202, Bralislava. HERAK , M. , SCAVNICAR, B., SUSNJARA, A. , DURDANOVIC, Z. , KRYSTY N, L. & GRUBER , B. ( 1983) : The Lower Triassic of Mue. Proposal fo r a standard section or the European Upper Scythian. ­ In: Neue Beilrage zur B iostratigraphic de l' Tcthys­ Trias. Osterreichi sche Akademie clef Wi ssen­ schal"len , Sehriftenrcihe der E rdwissensc haftli chen Kommissionen, 5, 93-106, Wien. TAJDER , M. & HERAK, M. ( 195 1): PClrografija i geo­ logija.- Skolska knjiga, Zagreb, VlII+23 I p. TAJDER , M. & HERAK, M. ( 1959): PClrografij a i gco­ logija. - 2nd ed. , Skolska knj iga, Zagreb, X+280 p. TAJDER , M. & HERAK , M. (1966): Pelrogral"ija i geo­ logija. - 3rd cd., Skolska knji ga, Zagreb, X+400 p. Doprinos prof. Heraka stratigrafiji trijasa "U Dinaridima Irijas je veoma dobro razvijen , pa predstavlja veoma vai an Clan sredozeml1og trijasa." (HERAK, 1984, p. 205) Prvih d vadcsctak godina znanstvenog facia profe­ sora Hc raka lllozemo slobodllo nazvati trijaskim peri­ odom. Asocirajuci na Irodjelnu podjelu Irijasa taj bismo period II jeclnoj ne rormalnoj kronoloskoj podjeli mogli nazvati "rani Herak" . "Srednj i Herak" bi obuhvat io "krski period", dok bi "kasni Herak" bio obiljezen geo­ Icktonikolll Dinarida. Sv oje zanim3njc za nasi age trij asa Herak l1loguce du gujc geoloskom kartirallju u ekip i pro fesora Salope­ ka , a vjerojatno i kasnijc ll1 radu na svoj oj dizertaciji kod Juliusa von Piae u Beeu (HERAK, 1943, 1944). U svojim ist razivanj imCl cesto obraduje svoj rodni zu m­ beracki kraj , pa jc i prvi njegov stratigrafski fad onaj 0 strati grafskom rasc lanji vanju l11 ezozojskih nasJaga j ugozapadllog d ije la Zumberackc gore (1-1 ERAK, 1947). U tOIll radu 011 ukratko navodi rezuhale dviju gco loskih ckskurzija u to podrucje. 0 iSlrazi vanj ima u susjcdnom Sa ll1oborskoll1 gorju izvj eslava HERAK ( 1954a, b, 1955), a zat im izlazi i njegov znacajni rad: "Geologija Sall1oborskog gOI]a" (HERAK, 1956a) , u koje ll1 dela­ Ijna opisuje stratigrafskc jed inice i tektonsku gradu tog podrucja. Osobitu paznju po klanja nas iagam 3 Iri jasa. Herakova istrazivanja pokazala su znalno vecu raspro­ slranj cnost nas laga donj eg trijasa nego sto sc ranij e mi slil o, a za gips, ranijc pripisivan donjcm trijasu, SI11(\­ tra da je paJeozojski. U srednjem i gornjcm trijasu raz­ likuje dolom ite, ladinicku mjciiovitu skriljavo-Iaporovi­ to-vapnenacku serij u s tufov ima i roznjacim a, Ie vc li ­ kOlrnske nasJage koje uvrstava u gornji lrijas, uz SUITI ­ nju da se radi 0 ladiniku. HERAK et al. (1965) na temc­ Iju makrofaune utvrduju gornjotrij asku starost dijc Ja karbonatnih sukces ija l1a podrucju Zumbcrka, te doka­ Zllju gornjokrednu starost velikotrnskih nasiaga. Poslje­ dnj i radovi u kojima navodi nove nalaze trijasa datiraju iz sezdesclih (HERAK, I 966b, 1968), ali svoju vczu sa stratigrafijom trijasa Zumberka nastavlja i u najnovije vrijeme kao recenzent l1a projckw geoioske kan e Republike Hrvatskc 1:50.000. Tstrazivanja trijaskih nas laga Herak provodi u okvirll reg ionalnih geo]oskih istrazivanja na podrucju Korduna i Like. Tako HERAK (I9540, I 956c) u podru­ cju rijcke Korane utvrduje znalno rasprostranjcnje tri - Koch 8.:. (jrga~(l\lic: Professor 1 krak's Contribut ion 10 Triassic Stral igraphy jaskih nas laga, posebno dololllita, na kojillla kontinui ­ rano s lijede dolomiti lijasa, a kasnije HERAK & BAHUN (1963) i HERAK & BOJANIC (1966) deta­ ljnije iSlrazlIjll trijaskc nasI age i dokazuju donji i gornji trijas. U svoj im radovim<-t Ilerak korisli "algll" Sphae­ I'ocodilllll bomclllonni kao dokaz gornjeg trijasa (l-TER­ AK, 1952a, b, 1956a, 1957, 1962, 1963, 1966b, 1968; IIERAK & llAIIUN, 1963; HERAK & BOIANIC, 1960). rako se pokazalo cia se ne radi 0 algi vee 0 sedi­ mcnloloskoj s irukiuri - onkoidu (IlAllIC, 1970) kara­ kle ri s licni slojevi s krupnim onkoidima i dan as sluze kao inclikacija gornjotrijaskih naslaga, gclje se eesto pojavljllju u vecem broju. HERAK (1950) vee ukazllje na vclik znacaj clazi­ kladalllih alga II stratigrafskoj razdiobi trijaskih sukce­ s ija, cime je povezao dva svoja inleresna podrucja. Kontinuirano prollcavajuci taksonomske odnose i st rati ­ gra fsku c1islribllc iju ovih alga, Herak ih koristi u rjdavanjll problelllatike stratigrafije trijasa u brojnim gcoloskilll radovillla. U podrucju Gracaea, HERAK ( 19.56b) na temelju dazikladalne norc odvaja anizicke od lacliniekih naslaga, te clokazllje diskordaneiju izmedll lad ini ka i karnika. Na istom lerenu HERAK ( 1960c) ulvrduj e diskordantan odnos izmeclu perma i trijasa, clokazujc srcdnji trijas POJllOCU alga provodnih za anizik i ladinik i upotpunjava intcrpretaciju diskordancije iZJllcdll sred nj eg i gornjeg trijasa. Obradujuci nasi age trijasa II okolici Sv. Roka u Lici HERAK (1965) jos jcdanpul potvrcluje vrijednosl daziklaclalnih alga u raz­ cliobi sreclnjeg trijasa na katove, te reviclira neke do tada poznale raspone pojeclinih vrsta. Profesor He rak je saznanja svoja i ostalih geologa sintctizirao i rcdov ito prezcntirao domacoj i svjctskoj gcoloskoj javnosli popularizirajuei tako nasu geologiju 1I svijctu. Stratigrariju lrijasa Hrvatske, koja se temelji na daziklaclalnilll algallla, akaclemik Herak je po prvi put a prezentirao svje tskoj geoloskoj javnosti na medll~ narodnom geoloskolll kongrcsu II Copenhagenu (HER­ A K, 1960b). Na Meclunarodnol11 kolokviju 0 trijasll 1I Monlpcllicru 196 1 (HERAK, 1962, 1963) prikazani SLI glavn i bioslratigrafski, lilOloski i palcogeografski odno­ saj i Irijasa 1I llrvatskoj , te naglasena llloga pojeclinih orogenclsk ih fanl za fonniranje lrijaskih naslaga i nji ­ hovu rasp rostranjcnosl. Na prec\avanju odrzanom u Geoloskom druslvu 1I Bceu HERAK ([ 966) naglasava 155 ulogu vapnenackih alga u strat igrafiji Dinarida. Na mcdunarodnom kolokviju 0 stratigrafiji trijasa II S10- vackoj , HERAK ct al. (1967) su dali korclaciju Irijasa Like, Pakleniee i Gorskog Kotara uz prikaz f'osilnc zajednicc s Iczislem na claziklada1ne algc. HERAK ([973b) daje prikaz novijih istrazivanja trijasa U Hrvat­ skoj , a HERAK (l987b) preglecl trijasa Dinaricla u svjc­ tIll pr ijclaza iZlllCdll herc inske i alpskc orogcncze. Na Illedllnarodnolll SilllPOZijll U Heeu 0 stratigrafiji alpsko-mcditeranskog Ir ijasa, HERAK (1974a) jc sazeo rezultatc svog rada na istrazivanju problelllatike lrijas­ kih naslaga Dinaricla s naglaskom na palcogcografiju i faeijese. l-1erak.ie vee tada ukazao na problclllatiku koja je jos i danas aktualna: " Pal eogeografski uvjeli fae i­ jesnog razvoja trijasa relativno uskog prostora hrvatskih Dinarida odrazavajll dinamiku bez jasnog vrel11enskog i faeijesnog preklapanja granicnih s lojeva razJiCi tih kato­ va i scrija. Stoga je primjena kronostr